Nonreciprocal parametric amplifier converter with internal pump



Feb. 22, 1966 MAURER L 3,237,017

NONRECIIROCAL PARAMETRIC AMPLIFIER CONVERTER WITH INTERNAL PUMP OriginalFiled Nov. 22. 1961 4 Sheets-Sheet l f8 E A f S C f0 IF PHASE SHIFTERPIC-3.3.

I I I A GL GS e I E 1 i Fl G 4b. L I INVENTORS Robert Mourer a oKarl-Heinz Licherer FIG .40. BYQMW/E W ATTORNEYS Feb. 22, 1966 MAURERETAL 3,237,017

NUNliECIlR-JCAL IARAMETRIC AMPLIFIER CONVERTER WITH INTERNAL PUMPOriginal Filed Nov. 22. 1961 4 Sheets-Sheet Z f -f in the frequencyinverting case f +f inihe frequency non inverting case f n'f 0 0 E 2 2 Ai a 4p 0 f PHASE SH'FTER INVENTORS l PUMP Robert Mourer 8i GENERATOR fpKarl-Heinz Locherer F|G.5. 4 W

ATTORNEYS Feb. 22. 1966 R MAURER ETAL 3,237,017

NONHIJCKHMCAL I'ARAME'I'RIC AMPLIFIER CONVERTER WITH INTERNAL PUMPGriginal Filed Nov, 22. 1961 4 Sheets-Sheet 4 f b1 I FY'Y\ 0 I A; l 1 HFI I l F I l I '-1| I I .M I a: ga m X I I I 5 L9 I W I l P4P E I 5 i-, Ii l I 5 I I Al; I I W I l J INVENTORS Robert Mourer 8 Karl-HeinzLicherer ATTORNEYS United States Patent 3,237,017 NONRECIPROCALPARAMETRIC AMPLIFIER CONVERTER WITH INTERNAL PUMP Robert Maurer andKarl-Heinz Locherer, Ulm (Danube),

Germany, assignors to Telefunken Patentverwertungs- G.m.b.H., Ulm(Danube), Germany Continuation of applications Ser. Nos. 154,144 and154,145, Nov. 22, 1961. This application Mar. 25, 1965, Ser. No. 442,691Claims priority, application Germany, Nov. 22, 1960, T 19,310, T 19,3119 Claims. (Cl. 307-883) This application is a composite continuation ofapplication Serial No. 154,144, filed November 22, 1961, and applicationSerial No. 154,145, filed November 22, 1961. I

The present invention relates generally to amplifiers and moreparticularly to an amplifier of the non-reciprocal type.

Such amplifiers include the arrangement of a cascade connection of oneup-converter and one down-converter, which may be parametric or tunneldiode mixers or converters. This type of circuit is especially suitablefor use with ultra-high frequencies. Circuits of this general type arealready known wherein a parametric downconverter is connected in tandemor cascade with a parametric up-converter. In order to obtainnon-reciprocal behavior characteristics in such a circuit, the necessarypumping voltages are fed out of phase, and the effect of a three-armedcirculator is achieved by means of two magic Ts and an additional phaseshifter. Such an arrangement, for example, can be found in Kamal,Proceedings of the IRE, August 1960, pages 1424-1430.

This known type of circuit requires a relatively large volume andtherefore can not be used in arrangements where an extremely smallconstructional volume or physical size is a requirement. Furthermore, anon-reciprocal parametric travelling wave amplifier is known whereinseveral reactance diodes are pumped with out of phase voltages so thatamplification is provided in the forward direction, while in the reverseor backward direction the amplification is equal to one.

However, for certain applications of such a non-reciprocal amplifierdevice, attenuation must be provided in the reverse direction.

With these defects of the prior art in mind, it is a main object of thepresent invention to provide a nonreciprocal amplifier circuit which maybe constructed to be of small physical size as compared to prior artararangements.

Another object of the invention is to provide a converter cascadearrangement which always exhibits nonreciprocal behavior with respect tothe magnitude of the transmitted signal by virtue of a compensatingnetwork which neutralizes the reactive admittance of the convertercascade.

A further objects of this invention is to prevent the radiation ofundesirable and disturbing voltages over the antenna.

Another object of the invention is to provide an arrangement of the typedescribed which prevents variations of the load admittance from havingan effect on the input admittance of the amplifier and vice versa, byneutralizing the reactive admittance of the amplifier to achieveamplitude non-reciprocity over a broad bandwidth.

These objects and others ancillary thereto are accomplished according toembodiments of the invention wherein a non-reciprocal amplifier circuitespecially adapted to ultra-high frequencies is constructed by means ofa cascade connection of one tip-converter and one down- 3,237,017Patented Feb. 22, 1966 ice converter, wherein the non-linear elements ofthese converters are modulated by a signal voltage and a pumping oroscillating voltage, respectively. One embodiment of the presentinvention uses, as the active element, a nonlinear real conductance forone converter or mixer, and a non-linear susceptance for the other mixeror converter. With this type of cascade arrangement having one converterwith a non-linear susceptance and a further converter with a non-linearreal conductance, a nonreciprocal behavior characteristic will always beexhibited with respect to the magnitude of the transmitted signal. Also,with respect to phase, the cascade arrangement is non-reciprocal.

In another embodiment, these may include an up-converter and adown-converter having similar non-linear admittances, that is, bothconverters have the same type of admittance, a susceptance orconductance which is non-linear, and they are controlled throughout therange by pumping voltages which are out of phase. When such an amplifierdevice is to be used as the input circuit for television receivers thereactive admittance of the mixer or converter cascade is neutralized byusing a linear passive and reciprocal coupling network between theamplifier elements, i.e., the mixers or converters. In thi'l case, bothamplifier elements will have either only nonlinear susceptance ornon-linear real conductance.

Additional objects and advantages of the present invention will becomeapparent upon consideration of the following description when taken inconjunction with the accompanying drawings in which:

FIGURE 1 is a block diagram of an embodiment of the present inventionwith two mixers in cascade.

FIGURE 2 is a more detailed circuit diagram of the embodimentillustrated in FIGURE 1.

FIGURE 3 is a block diagram of an embodiment of the present inventionbased on that of FIGURE 1, with three mixers in cascade.

FIGURES 4a and 4b are alternative circuit diagrams showing an embodimentof the present invention wher in the internal impedances of thegenerator and load connected to the device are used instead of providingresonant circuits at the input and output of the device as shown, forinstance, in FIGURE 2. The vertical lines a and b in FIGURES 4a and 4bare correlated with the lines a and b in FIGURE 2.

FIGURE 5 is a block diagram of another embodiment of the presentinvention with two mixers in cascade.

FIGURE 6 is a more detailed circuit diagram of the embodimentillustrated in FIGURE 5.

FIGURE 7 is a block diagram of an embodiment of the present inventionbased on that of FIGURE 5, with three mixers or converters in cascade.

With more particular reference to FIGURE 1, the two converters or mixersM and M are connected in tandem or cascade. One is an up-converter andthe other is a down-converter. This circuit is provided with an input Eand an output A. One of the two converters is provided with a non-linearsusceptance S while the other has a non-linear real conductance C. Inthe particular embodiment illustrated in FIGURE 1, the non-linearsusceptance S is arranged in the first converter M The susceptance S ispreferably provided by a capacitance diode since it has a non-linearcharge-voltage characteristic curve. Instead of this capacitance diode,a current sensitive inductance or a pre-rnagnetized ferrite device maybe used to provide the non-linear susceptance, since thecurrent-magnetic flux characteristic curves of these elements are alsonon-linear. The non-linear real conductance C may be provided by aconventional type of mixer diode or by an Esaki diode, which is a tunneldiode whose current volt-age characteristic curve has a partiallydescending slope.

For some purposes of application, a circuit is required having an inputwhich is completely decoupled with respect to its output. Therefore, thepresent invention proposes to, provide for the neutralization of thereactive admittance of the cascade arrangement by connecting a passivelinear and reciprocal coupling network K between the input E and theoutput A of the circuit illustrated.

If the first converter is an up-converter and the second converter isprovided with a tunnel diode, then a transducer gain or amplificationlarger than unity is possible. The two converters M and M are fed with apumping frequency or oscillating frequency f from an oscillator O. thefeeding may be in phase, or, as has been indicated in the drawing, outof phase. If out of phase, then a phase shifting device p is providedbetween the two converters. When the cascade arrangement is operated inthe frequency noninverting case, wherein the idle frequency is equal tothe sum of the signal frequency and pumping frequency, i.e., f =f +f theneutralization mentioned hereinabove is accomplished by an inductancewhen there is resonance, if the two pumping voltages for the twoconverters are in phase. On the other hand, when the pumping voltagesare in phase opposition, a capacitance is used for neutralizationpurposes.

Moreover, when the converter cascade arrangement illustrated in FIGURE 1is operated in the frequency non-inverting case, power matching ispossible between the input and the output. When it is operated in theinverting case and with the pumping voltages in phase, theneutralization may be provided by using an inductance. On the otherhand, with the pumping voltages in phase opposition, a capacitance isuse-d for neutralization purposes. The cascade arrangement illustratedmay be operated in a reverse or inverse direction, i.e., the input E maybe used as the output A and vice versa. In order to simplify the circuitit is advisable to provide a common resonant circuit for the idlefrequency for the two converters, as shown in FIGURE 2.

, The circuit shown in FIGURES 1 and 2 may, according to the presentinvention, be extended to be a non-reciprocal mixer circuit by theaddition of a further upconverter or down-converter, as shown in FIGURE3. Such a mixer circuit is especially useful as the input circuit forultra-high frequency and very high frequency tuners for televisionreceivers. Such a circuit may be substantially decoupled in the reversedirection from output A to input B so that undesired radiation of theoscillator frequency over the antenna is eliminated by neutralizing thereactive admittance. When such a circuit is used for televisionreceivers it is preferable to use a self-oscillating grounded-gridmixing stage as the third mixer or converter. The input circuit of atelevision receiver must, of course, be capable of being tuned throughits operating range.

Usually, frequency sensitive resonant circuits are provided at the inputE and at the output A of the cascade arrangement. Instead of using theseresonant circuits, the real frequency independent inherent resistance Gof the signal generator which is the input, and the load 6;, may be useddirectly, as shown in FIGURES 4a and 4b. FIGURES 4a and 4b showcircuitry replacing that indicated as 1 and 2, respectively, in FIGURE2. In other words, the internal impedances of the generator and loadconnected to the device are used instead of providing resonant circuitsat the input and output.

The above-described embodiments of the invention render it possible todesign a non-reciprocal circuit in a simple manner and which exhibitsthe behavior of a socalled isolator in one direction, and which in spiteof this renders it possible to have an amplification in the oppositedirection.

It is to be noted that although an Esaki diode having a current-voltagecharacteristic curve with a partially descending slope may be used asthe non-linear real conductance, a conventional mixer diode having acontinuously ascending current-voltage characteristic curve may also beused for this purpose.

When the circuit is operated in the frequency inverting case, then inaddition to the signal frequency and the pump frequency, of all ofthefrequencies which may be obtained by mixing the signal frequency iand the pumping frequency f only the difference frequency f f is used.This is accomplished by providing the circuit with resonant circuitswhich are in each case tuned to the appropriate frequencies, see FIGURE2.

When the circuit is operated in the frequency non-inverting case, thenof the many mixed frequencies which are obtained, only the sum frequencyf +f is used. For this purpose, a circuit is provided with appropriatelytuned resonant circuits, see FIGURE 2.

A further embodiment of the invention is illustrated in FIGURE 5, whichshows an amplifier device including a cascade connection of twoparametric or tunnel diode amplifier elements M and M which may beconverters or mixers. One of these is an up-converter, while the otheris a down-converter. These'two amplifier elements may have either anon-linear susceptance or non-linear real conductance. This embodimentdiffers from that shown in FIGURES 1 through 4 in that the latterembodiment utilizes mixers which have different types'of nonlinearconductance, whereas in this embodiment, converters of the same type areutilized. These non-linear elements are indicated as D and D in FIGURES5 through 7. The susceptance may be provided by a capacitance diode forexample, since this has a non-linear chargevoltage characteristic curve.It is also possible to use a pre-magnetized ferrite body or a currentsensitive inductance, since their current-magnetic-flux characteristiccurves are also non-linear.

A linear passive and reciprocal coupling network K is provided betweenthe. input E and the output A in order to neutralize the reactiveadmittance of the cascade arrangement M M Out-of-phase pumping voltagesof the frequency f are fed to the two amplifier elements, and in thepresent embodiment this is accomplished by means of a phase shifter P.The two non-linear susceptances or conductances are controlledthroughout the entire range by means of these voltages.

When the circuit is operated in the so-called frequency inverting case,then in addition to the signal frequency and the pump frequency, of allof the frequencies which may be obtained by mixing the signal frequencyf and the pump frequency f only the difference frequency f f is used.This is accomplished by providing the circuit with resonant circuitswhich are in each case tuned to the frequency i or f or f frespectively, as shown in FIGURE 6. By this means a complete decouplingbetween the signal output and the signal input in the reverse directionis possible, while in the forward direction a transducer gain of morethan unity is obtainable. By

- damping the input and output circuits the transducer gain may bereduced to unity, and at the same time a power, or impedance matchingmay be effected so that the circuit acts as an isolator.

When this circuit is operated in the so-called frequency non-invertingcase, then of the many mixed frequencies which are obtained, only thesum frequency f +f is used. For this purpose, a circuit is provided withappropriate tuned resonant circuits. In the reverse or backwarddirection a complete decoupling may be obtained with this circuit. Powermatching may be obtained because of the positive input and outputconductances which appear. The transducer gain is then substantiallyequal to unity if only smallcircuit losses are encountered.

When the circuit is operated in the frequency noninverting case thefirst converter M is an up-converter. If the circuit is used in thefrequency inverting case, the first converter is an up-converter only ifthe frequency f f is larged than f However, in the event that 3,- issmaller than f,, the first converter is a down-converter.

The addition of coupling network K converts the nonreciprocalcharacteristic of this circuit with respect to phase, into oneexhibiting non-reciprocal behavior with respect to magnitude.

In another embodiment of the invention the non-reciprocal amplifierdevice of FIGURES 5 and 6 may be enlarged upon to form a non-reciprocalmixer circuit shown in FIGURE 7, by additionally providing a furtherup-converter or down-converter M When the circuit is to be used fortelevision tuners, it is particularly advantageous to use aself-oscillating grounded-grid mixing stage as the third mixer orconverter M In this case, the oscillating stage then, at the same time,generates the required pumping voltage for the first two converters Mand M The harmonic frequency is derived from the self-oscillating mixingstage M By this means the non-linear elements D and D of the first twoconverters are modulated. In this case when the circuit is operated inthe frequency inverting case the pump frequency must satisfy thefollow-v ing conditions:

f =fs+fi= fo= (fs+frn) These symbols denote: f =pump frequency f =signalfrequency f =idle frequency f =fundamental oscillation of thegrounded-grid stage f =intermediate frequency of the following stage n=apositive integer.

From this relationship the electrical design, i.e., the components andtheir values, of the idle circuits of the two parametric or tunnel diodeconverters M and M may be derived. These idle circuits must then betune-d to the frequency f f (n-l)+n- Assuming a given signal frequency1, of 500 megacycles per second and a required intermediate frequency of50 megacycles per second, and an n .value of 3, the result is an idlefrequency f of 1150 megacycles per second. The pump frequency used is1650 megacycles per second, and the fundamental oscillation of theself-oscillating groundedgrid mixing stage is 550 megacycles per second.

Instead of the resonant circuits which are normally present at the inputand output of the circuit, the real frequency-independent inherentresistances of the generator and the load can also be used directly, asshown in FIGURES 4a and 4b with respect to the embodiment of FIGURE 1.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes andadaptions, and the same are intended to be comprehended within themeaning and range of equivalents of the appended claims.

What is claimed is:

1. A non-reciprocal amplifier circuit arrangement, especially forultra-high frequency, comprising, in combination:

(a) an up-converter and a down-converter connected in a cascadearrangement and having non-linear elements, said cascade arrangementhaving an input and an output;

(b) a source of signal voltage for feeding the cascade arrangement and asource of pump voltage for controlling the non-linear elements, one ofsaid converters having an active element which is a nonlinear realconductance and the other converter having a non-linear susceptance; and

(c) a passive linear and reciprocal coupling network provided betweenthe input and the output of the cascade arrangement for neutralizing thereactive admittance.

2. A non-reciprocal amplifier circuit arrangement as defined in claim 1and including a further converter connected in cascade with saidfirst-mentioned converters for forming, in combination therewith, anon-reciprocal mixer.

3. A non-reciprocal amplifier circuit arrangement as defined in claim 2,said circuit arrangement including, instead of the resonant circuits ofthe input E and the output A of the cascade arrangement, the realfrequencyindependent inherent resistances of the connected generator andload applied directly.

4. A non-reciprocal amplifier circuit arrangement, especially forultra-high frequency, comprising, in combination:

(a) an upconverter and a down-converter connected in a cascadearrangement and having non-linear elements, said cascade arrangementhaving an input and an output;

(b) a source of signal voltage for feeding the cascade arrangement and asource of pump voltage for controlling the non-linear elements, one ofsaid converters having an active element which is a nonlinear realconductance, and the other converter having a non-linear susceptance;and

(c) a passive linear and reciprocal coupling network provided betweenthe input and the output of the cascade arrangement for neutralizing thereactive admittance, said circuit being arranged to operate in thefrequency non-inverting case, said pump source providing in-phasepumping voltages to the two converters, said coupling network being aninductance element for providing neutralization.

5. A non-reciprocal amplifier circuit arrangement, especially forultra-high frequency, comprising, in combination:

(a) an up-converter and a down-converter connected in a cascadearrangement and having non-linear elements, said cascade arrangementhaving an input and an output;

(b) a source of signal voltage for feeding the cascade arrangement and asource of pump voltage for controlling the non-linear elements, one ofsaid converters having an active element which is a non-linear realconductance, and the other converter having a non-linear susceptance;and

(c) a passive linear and reciprocal coupling network provided betweenthe input and the output of the cascade arrangement for neutralizing thereactive admittance, said circuit being arranged to operate in thefrequency non-inverting case, said pump source providing out-of-phasepumping voltages to the converters, said coupling network being acapacitance element for providing neutralization.

6. A non-reciprocal amplifier circuit arrangement, especially forultra-high frequency, comprising, in combination:

(a) an up-converter and a down-converter connected in a cascadearrangement and having non-linear elements, said cascade arrangementhaving an input and an output;

(b) a source of signal voltage for feeding the cascade arrangement and asource of pump voltage for controlling the non-linear elements, one ofsaid converters having an active element which is a non-linear realconductance and the other converter having a non-linear susceptance; and

(c) a passive linear and reciprocal coupling network provided betweenthe input and the output of the cascade arrangement for neutralizing thereactive admittance, said circuit being arranged to operate in thefrequency inverting case, said pump source providing in-phase pumpingvoltages, said coupling network being an inductance element forproviding neutralization.

7. A non-reciprocal amplifier circuit arrangement, especially forultra-high frequency, comprising, in combination:

(a) an up-converter and a down-converter connected in a cascadearrangement and having non-linear elements, said cascadearrangernenthaving an input and an output; x Y

(b) a source of signal voltage for feeding the cascade arrangement and asource of pump voltage for controlling the non-linear elements, one ofsaid converters having an active element which is a non-linear realconductance, and the other converter having a non-linear susceptance;and

(c) a passive linear and reciprocal coupling network provided betweenthe input and the output of the cascade arrangement for neutralizing thereactive admittance; said circuit being arranged to operate in thefrequency inverting case, said pump source providing out-of-phasepumping voltages, said coupling network being a capacitance element forproviding neutralization. 8. A non-reciprocal amplifier device suitablefor use i as an input circuit for television receivers, comprising, in

combination:

(a) two converters connected in cascade and having only one type ofnon-linear admittance;

(b) means for feeding out-of-phase pumping voltages to said converters;

(c) a linear passive and reciprocal network coupling said converters toneutralize the reactive admittance of the converter cascade; and

((1) a further converter connected in cascade with said two convertersto form a non-reciprocal mixer circuit, said further converter being aself oscillating ground-grid mixing stage connected to supply the thepumping voltage for said two converters and thus defining at least aportion of said pumping voltage feeding means. 9. A non-reciprocalamplifier device suitable for use as an input circuit for televisionreceivers, comprising, in

combination:

(a), two converters connected in cascade and having only one type ofnon-linear admittance;

(b) means for feeding out-of-phase pumping voltages to said converters;i

p (c) a linear passive and reciprocal network coupling said convertersto neutralize the reactive admittance of the converter cascade; and

(d) a further converter connected in cascade with said two converters toform a non-reciprocal mixer circuit, said further converter being aself-oscillating grounded-grid mixing stage connected to supply thepumping voltage for said two converters and thus defining at least aportion of said pumping voltage feeding means;

(e) said converters being arranged so that the circuit is operated inthe frequency inverting case and a harmonic frequency coupled out of theself-oscillating grounded-grid stage serves as the pump frequency sothat the following condition is satisfied:

where: V

f =pump frequency =signal frequency f =idle frequency f =fundarnentaloscillation of the grounded-grid stage f =intermediate frequency of thefollowing stage n=a positive integer.

Fisher, Proceedings of the IRE, July 1960, pages 1227-l232.

Kamal, Proceedings of the IRE, August 1960, pages 14241430.

ROY LAKE, Primary Examiner]

1. A NON-RECIPROCAL AMPLIFIER CIRCUIT ARRANGEMENT, ESPECIALLY FORULTRA-HIGH FREQUENCY, COMPRISING, IN COMBINATION: (A) AN UP-CONVERTERAND A DOWN-CONVERTER CONNECTED IN A CASCADE ARRANGEMENT AND HAVINGNON-LINEAR ELEMENTS, SAID CASCADE ARRANGEMENT HAVING AN INPUT AND ANOUTPUT; (B) A SOURCE OF SIGNAL VOLTAGE FOR FEEDING THE CASCADEARRANGEMENT AND A SOURCE OF PUMP VOLTAGE FOR CONTROLLING THE NON-LINEARELEMENTS, ONE OF SAID CONVERTERS HAVING AN ACTIVE ELEMENT WHICH IS ANONLINEAR REAL CONDUCTANCE AND THE OTHER CONVERTER HAVING A NON-LINEARSUSCEPTANCE; AND (C) A PASSIVE LINEAR AND RECIPROCAL COUPLING NETWORKPROVIDED BETWEEN THE INPUT AND THE OUTPUT OF THE CASCADE ARRANGEMENT FORNEUTRALIZING THE REACTIVE ADMITTANCE.